Rotatable chair



4 Sheets-Sheet 1 H. MlCHALSHI ROTATABLE CHAIR Fig. 1

Nov. 16 1965 H. MICHALSHI ROTATABLE CHAIR 4 Sheets-Sheet 2 Filed May 25, 1964 3 M F 6 7 fl Vin/ 6 n W 1 Fl:

Nov. 16, 1965 H. MICHALSHI 3,218,021

ROTATABLE CHAIR Filed May 25, 1964 4 Sheets-Sheet 3 Fig.4 i v 'r- /5-- 4 a 17 fi Z18 Nov. 16, 1965 H. MICHALSHI ROTATABLE CHAIR 4 Sheets-Sheet 4 Filed May 25, 1964 llnited States Patent 3,218,021 RGTATABLE CHAIR Heinz Michalshi, Marker Breite 23, Korbach, Germany Filed May 25, 1964, Ser. No. 369,764 Claims priority, application Germany, Nov. 2, 1963, M 58,769 4 Claims. (Cl. 248-401) This invention relates to chairs having a seat member which is rotatable and adjustable vertically with respect to the supporting column or standard.

More particularly, the present invention relates to chairs wherein a seat member i mounted on spring means and is adjustable vertically by means of a threaded spindle supported within a column or standard and nut means cooperable with the spindle.

In rotatable chair structures, it has been customary to use spiral springs as the spring mean and locate the springs around the spindle within the column or standard, and such an arrangement consumes considerable space. Furthermore, with this arrangement, the nut which is also disposed in the standard must be unlocked by levers or bolts actuated exteriorly of the standard for avoiding an undesired height displacement of the seat in the loaded condition. It is only after the nut has been locked that the spindle can be adjusted vertically. The assembly of rotatable chairs of such character cannot be accomplished without special equipment and requires considerable time.

Hence, the problem involved in the art is to combine spring components and adjusting means in such a fashion that such components are available as a prefabricated unit prior to the final assembly of the rotatable chair. Additionally, it should be possible to effect a vertical adjustment of the seat member without the actuation of special locking devices as well as a reduction of the heretofore required dimensions of the chair in the zone of the column or standard.

According to the invention, these objects are achieved by mounting at least three truncated conical springs in parallelism within a bell-shaped nut which extends over the end of the column or standard with the lower ends of the springs engaging a support plate which is non-rotatable yet axially shi'fta'ble with respect to the nut up to a limit element for assuring spring tensioning and with the bottom face of the support plate adjoining a support bearing means for the spindle.

Other and further objects of the invention will be apparent to those skilled in the art from the following detailed description of the annexed drawings which by way of a preferred example only, illustrate an embodiment of the invention.

In the drawings:

FIG. 1 is a view inside elevation and partly in cross section of the invention,

FIG. 2 is a plan View of FIG. 1,

FIG. 3 is a view taken along the line A-B of FIG. 2, the view looking in the direction of the arrows,

FIG. 4 is a view taken along the line C-D of FIG. 2, the view looking in the direction of the arrows,

FIG. 5 is a plan view of the support plate,

FIG. 6 is a view taken along the line E-F of FIG. 5, the view looking in the direction of the arrows,

FIG. 7 is a view in perspective and partly broken away illustrating the bellshaped nut, the support plate and end abutment, and

FIG. 8 is a view in perspective partly broken away illustrating the bearing, threaded spindle and the connection between the bearing and spindle for allowing axial movement yet nonrotatable movement to the bearing.

As shown in the drawings, a spindle 1 having an ex- "ice ternal screw thread is mounted for rotatable and vertical adjustable movements within a column or standard 11 for the chair. A seat member S is supported by the upper end of the spindle 1 and a base B is provided for the lower end of the column 11. A nut 2 which is substantially bell-shaped is adapted to engage threadedly the external threads of the spindle 1 as indicated at 14 and the lower end of the nut extends below flared upper end 4 of the column 11.

With reference to FIGS. 1 and 2, four truncated conical springs 3 are located within the nut 2 and are arranged symmetrically about the circumference of the spindle 1. The springs 3 are positioned in outwardly bowed portions 15 formed in the inner periphery of the nut. The upper ends of the spring 3 bear against the closed end of the nut 2 while the lower ends bear against a generally circular support plate 6. The plate 6 is nonrotatably mounted on the spindle 1 but such plate is capable of axial movement relative to the spindle.

More specifically, and attention is directed to FIGS. 5 and 7, the support plate 6 is provided with outwardly extending enlargements or base 16 which engage the portions 15 and can be shifted against the pressure of the springs 3 but cannot be rotated relative to the nut 2. To provide for prestressing of the springs 3, the plate 6 rests on an end abutment 5 constituted by an expansible ring which is received by a groove 17 formed in the nut 2 (FIG. 4). A support bearing 7 for the spindle 1 is located adjacent the bottom or lower surface of the plate 6.

The bearing 7 is preferably made of synthetic material and is formed with a downwardly tapered stepped surface 10 as shown in FIGURE 8 and which surface lies slidingly against the flared upper end 4 of the column 11. The support plate 6 on its underside is provided with projections 8 which engage corresponding projections 9 formed on the bearing 7. By virtue of the above coupling means, the spindle 1, while the seat is loaded, is prevented from accidentally changing its vertical position due to rotation. As disclosed in FIGURE 8, the bearing 7 is so mounted that it can be displaced axially on the spindle 1 but cannot be rotated therewith. More specifically, the spindle 1 is provided with an axially extending groove 1a into which extends a projection 7a on the bearing 7. When the seat member is loaded, the projections 8 of the plate 6 engage the projections 9 of the bearing 7 so that no relative movement in the circumferential direction can occur between the spindle 1 and the nut 2 as the bearing 7 is held against rotation by the engagement of the projection 7a in the groove 1a. It is only when the seat member is unloaded that an adjustment in height can be made and this is effected by rotating the nut 2 manually. During this operation the projections 8 and 9 are not interlocked or intel-engaged so that relative rotation between the plate 6 and bearing 7 can be effected.

The spindle 1 is held firmly by the seat member and upon rotation of the nut 2, depending upon the direction of rotation threads itself either upward or downward in the thread of the nut 2.

The flared end 4 of the column 11 also functions as an abutment for locking component 13 which is fitted within the nut 2 so as to contact the end 4 from beneath and such component is secured within the nut by means of an expansible ring 12 which is received in groove 18 of the nut (FIGS. 1 and 4).

The assembly of the chair can be effected very simply and easily. Initially, the springs 3 are inserted into the outwardly bowed portions 15 of the nut 2. Next, the support plate 6 is inserted from below into the nut 2 with the enlargements 16 positioned in the portions 15 and the plate is forced upwardly somewhat against the pressure of the springs 3. Thereafter, the end abutment 5 is sprung into the groove 17.

Hence, the nut 2, springs 3 and support plate 6 constitute a pro-assembled unit.

The spindle 1 is then threaded into thread 14- of the nut 2 and after the bearing 7 has been forced from below against the nut 2, the spindle 1, together with the nut 2, springs 3, plate 6 and bearing 7 is inserted into the column 11. After the insertion of the locking component 13 which is secured by means of the expansible ring 12, the entire adjusting and rotating mechanism of the chair is fully mounted. Obviously, such components may readily and easily be detached in the event repair or replacement is necessary.

Inasmuch as there is no threaded connection between the support plate 6, bearing 7 and spindle 1, pressure loads on the spindle can be absorbed elastically by the springs 3 through the thread and nut 2 thus providing a resilient seat adjustable in its vertical position.

The invention is not to be construed to any strict conformity to the showings in the drawings, but changes or modifications may be made therein so long as such changes or modifications marl; no material departure from the spirit and scope of the appended claims.

What is claimed is:

l. A rotatable chair including a column having an upper end, a threaded spindle mounted within said col umn and having a portion projecting beyond said upper end, a bell-shaped nut threadedly engaging said projecting portion of said spindle and overlapping said upper end of said column, said projecting portion being adapted to carry a seat, a support plate within said nut which is nonrotatable yet axially movable relative to said nut, a plurality of truncated conical springs arranged within the nut in parallelism with the upper ends of the springs engaging the end of the nut and the lower ends of the springs engaging said support plate, an abutment within said nut and below the support plate for limiting axial movement of the support plate in a direction away from the end of the nut, and a bearing for the spindle below the support plate whereby upon the seat being loaded and the spindle rotated, the plate is engaged with the hearing so that no relative rotation occurs between the spindle and the nut but when the seat is unloaded, the support plate is disengaged sutiiciently from the bearing under the action of said springs for permitting relative rotation between the support plate and bearing whereby the nut can be rotated.

2. A rotatable chair including a column having a flared upper end, a threaded spindle mounted within said colurnn and having a portion projecting beyond said upper end, a bell-shaped nut threadedly engaging said projecting portion of said spindle and overlapping said upper end of said column, said projecting portion being adapted to carry a seat, a support plate within said nut which is non-rotatable yet axially movable relative to said nut, a plurality of truncated conical springs arranged within the nut in parallelism with the upper ends of the springs engaging the end of the nut and the lower ends of the springs engaging said support plate, an abutment within the nut and below the support plate for limiting axial movement of the support plate in a direction away from spot the end of the nut, a non-rotatable yet axially movable bearing for said spindle below the support plate, said bearing having a downwardly stepped surface in sliding contact with the flared upper end of the column, cornplemental projection on said support plate and bearing respectively for connecting the support plate and bearing when the seat is loaded, and a locking component fitted into said not and engaging the outer surface of said flared upper end whereby upon the seat being loaded and the spindle rotated, the projections are interengaged so that no relative rotation occurs between the spindle and not but when the seat is unloaded, the projections disengage sufliciently under the action of said springs for permitting relative rotation between the support plate and bearing whereby the nut can be rotated.

3. The rotatable chair as claimed in claim 2, in which said bearing is of synthetic material.

A rotatable chair including a column having an upper end, a threaded spindle mounted within said column and having a portion projecting beyond said upper end, a bell-shaped nut threadedly engaging said projecting portion of said spindle and overlapping said upper end of said column, said projecting portion being adapted to carry a seat, a support plate mounted within said nut, the inner wall of said nut being provided with a plurality of outwardly bowed recesses, a plurality of truncated conical springs within the nut with each spring being located in an outwardly bowed recess, a plurality of enlargements on said support plate with each enlargement being located in an outwardly bowed recess whereby said support plate is non-rotatable yet axially movable relative to said nut, the upper ends of said springs engaging the end of the nut and the lower ends of the springs engaging said enlargements, an abutment within the nut below the support plate for limiting axial movement of said plate in a direction away from the end of the nut, and a bearing for said spindle below said support plate whereby upon the seat being loaded and the spindle rotated, the plate is engaged with the bearing so that no relative rotation occurs between the spindle and the nut but when the seat is unloaded, the support plate is disengaged suiilciently from the bearing under the action of said springs for permitting relative rotation between the plate and bearing whereby the not can be rotated.

References Cited by the Examiner UNITED STATES PATENTS 1,067,961 7/1913 Bailey 248-401 1,129,175 2/1915 Desselle et al 248-401 1,270,729 6/ 1918 Harris 248-403 1,880,18l 9/1932 Turner 24840l 2,298,230 10/1942 Radke 248-400 2,590,382 3/1952 Danielson 248157 3,059,888 10/1962 Lie 248161 CHANCELLOR E. HARRIS, Primary Examiner.

CLAUDE A. LE ROY, Examiner. 

1. A ROTATABLE CHAIR INCLUDING A COLUMN HAVING AN UPPER END, A THREADED SPINDLE MOUNTED WITHIN SAID COLUMN AND HAVING A PORTION PROJECTING BEYOND SAID UPPER END, A BELL-SHAPED NUT THREADEDLY ENGAGING SAID PROJECTING PORTION OF SAID SPINDLE AND OVERLAPPING SAID UPPER END OF SAID COLUMN, SAID PROJECTING PORTION BEING ADAPTED TO CARRY A SEAT, A SUPPORT PLATE WITHIN SAID NUT WHICH IS NONROTATABLE YET AXIALLY MOVABLE RELATIVE TO SAID NUT, A PLURALITY OF TRUNCATED CONICAL SPRINGS ARRANGED WITHIN THE NUT IN PARALLELISM WITH THE UPPER ENDS OF THE SPRINGS ENGAGING THE END OF THE NUT AND THE LOWER ENDS OF THE SPRINGS ENGAGING SAID SUPPORT PLATE, AN ABUTMENT WITHIN SAID NUT AND BELOW THE SUPPORT PLATE FOR LIMITING AXIAL MOVEMENT OF THE SUPPORT PLATE IN A DIRECTION AWAY FROM THE END OF THE NUT, AND A BEARING FOR THE SPINDLE BELOW THE SUPPORT PLATE WHEREBY UPON THE SEAT BEING LOADED AND THE SPINDLE ROTATED, THE PLATE IS ENGAGED WITH THE BEARING SO THAT NO RELATIVE ROTATION OCCURS BETWEEN THE SPINDLE AND THE NUT BUT WHEN THE SEAT IS UNLOADED, THE SUPPORT PLATE IS DISENGAGED SUFFICIENTLY FROM THE BEARING UNDER THE ACTION OF SAID SPORINGS FOR PERMITTING RELATIVE ROTATION BETWEEN THE SUPPORT PLATE AND BEARING WHEREBY THE NUT CAN BE ROTATED. 